Polymeric materials are often converted into useful objects with pre-determined, three-dimensional shapes. Processes for manufacturing such objects typically involve first providing a low viscosity composition that is formed into the desired shape and then increasing the viscosity of the composition to maintain the shape. This typically involves providing a liquid composition, transforming into the desired shape, and converting into a solid. There are several variations of this process. For example, the liquid composition can be a solution of the polymeric material dissolved in an organic solvent or an aqueous dispersion of the polymeric material; the composition is transformed from a liquid into a solid by evaporation of an organic solvent or water. Alternatively, a liquid, reactive monomeric and or oligomeric polymer composition is formed into the desired shape and then transformed into a solid by a chemical reaction. In another variation, a polymeric composition is heated in order to transform it into a liquid and then cooled after being formed into the desired shape. These manufacturing processes all have shortcomings, which are described in greater detail in the following paragraphs.
Evaporation of a solvent (water or an organic solvent) from a composition is time consuming and therefore restricted to thin layers. This process is also dependent on temperature and humidity and involves loss of volume and thus shrinkage of the composition that can be severe enough that it results in cracking. Moreover, solvent evaporation presents environmental and health and safety issues. Although polymeric compositions processed as a monomeric and or oligomeric compositions are not sensitive to shrinkage and cracking problems, these materials are generally toxic and often contain reactive functionalities, including isocyannates, epoxides, amines, acrylates, and the like. Cure of these systems may be exothermic and the heat generated often has undesireable effects. Polymeric compositions processed by heat also do not have the level of shrinkage problems as the organic solvent and water-based materials and are relatively non-toxic. However, heat sensitive materials can not be processed by this means. Also, there is a risk of injury in processing polymeric materials with heat.
Therefore, the development of new compositions which can be shaped into desired forms without the aforementioned disadvantages would permit the more efficient manufacture of improved objects for consumer and industrial use.